Working in batches, puree soup in blender until smooth, adding more broth by 1/4 cupfuls to thin to desired consistency. Return soup to pot. Season to taste with salt and pepper. DO AHEAD: Can be made 1 day ahead. Refrigerate uncovered until cold, then cover and keep refrigerated.

Puree chives, grapeseed oil, and pinch of salt in blender until smooth.

Preheat oven to 375°F. Arrange pancetta slices in single layer on rimmed baking sheet. Roast until pancetta is browned and crispy, about 18 minutes. Transfer to paper towels to drain. Crumble pancetta. DO AHEAD: Chive oil and pancetta can be made 2 hours ahead. Let stand at room temperature.